This application is based upon and claims priority of Japanese Patent Applications No. 10-273822 filed Sep. 28, 1998, and No. 11-262099 filed Sep. 16, 1999, the contents being incorporated herein by reference.
The present invention relates to an electronic information displaying method and an electronic information browsing apparatus to browse through an electronic information. More particularly, the present invention relates to an electronic information displaying method and an electronic information browsing apparatus to easily browse through an electronic document having links which are defined by a hypertext format or the like.
The rate of distribution of electronic information including multimedia is increasing through networks such as the Internet, as well as data broadcasting by communication satellites and cable television, or through mediums such as CD-ROM, DVD-ROM or the like. Moreover, even in a local environment such as a person or a company, the demand for directly distributing electronically documents which are generated and edited on a computer and the demand for retrieving and browsing the contents of such documents on a display, such as a terminal unit, can be anticipated to increase in the future.
Here, electronic information is assumed to include character information, stationary images, moving images, audio signals, music information, document format information and link information.
The WWW (World Wide Web) is a current distribution mode for electronic information. In this case, electronic information is accumulated in a server which is connected throughout the world by way of the Internet. An electronic information is then transferred to a client from the server depending on a demand from a computer on the client side connected to the Internet. Thereby, contents of such electronic information is displayed on the display screen of the client computer for the convenience of browsing. In general, a software called a browser is used to display contents of the electronic information on the client computer.
HTML (Hypertext Markup Language) is mainly used as the language of choice for describing the electronic information in the WWW. HTML is a kind of language for describing hypertext (hereinafter, an electronic information described by a description language such as HTML is described as an xe2x80x9celectronic documentxe2x80x9d or only as a xe2x80x9cdocumentxe2x80x9d for the convenience of explanation).
In regard to the electronic document hypertext, a link to the other related document from the particular place in a document is defined, a document of the link destination can immediately be displayed when a user requests by designation the link information in the document. In the current HTML, it is possible to bury a stationary image, a moving image, an audio signal, music data, a program or the like and link them, in addition to the text documents.
As the browser software to read electronic documents described by HTML or the like, Netscape Navigator of Netscape Communication and Internet Explorer of Microsoft can be listed. Moreover, as the software to display an electronic document described in PDF (Portable Document Format) developed by Adobe Systems, the Adobe Acrobat Reader has been distributed from the same company.
The browser software explained above generally acquires, when a URL (Uniform Resource Locator) for defining existence of document definition data on the network is designated by a user, the document definition data indicated by such URL from the network, etc. to analyze contents of the acquired document definition data in view of forming a display image to be displayed on the screen.
A URL can be designated by a user through direct input using a keyboard or the like, or a URL which has been previously registered, such as the bookmark information, may be selected and called from a menu, etc. In addition, when a previously registered URL of an electronic document is to be displayed at the time of starting the browser, the browser acquires the document definition data indicated by the registered URL each time it is activated and then automatically displays the contents of such URL.
When a document is displayed on the display screen of the browser to define the link to the other document from the relevant document, the part for which the link is defined on the document is displayed in a different color of characters or with a display of the frame particularly colored for an icon in order clarify that the link is defined for such part. When a part corresponding to the link explained above is designated (i.e. selected) by a user with a designating means (such as mouse or the like), the browser acquires the document definition data of the link destination and displays the contents on the display screen.
In this case, an electronic document at the link destination is displayed in place of the document being displayed in the window of the browser or in the window which is newly opened.
Here, a user can read the document being displayed in the window through scrolling. Moreover, such a document can also be displayed by changing the font size. However, in general, the document is displayed in such a condition that it is adhered in the predetermined size to the display screen and therefore it is impossible to observe the document from the desired position or direction and to display the document while it is continuously expanded or compressed for the display. This point is far different from the feeling of browsing a document which is written on paper and also interferes with a comfortable feeling of browsing the electronic documents.
Meanwhile, the Adobe Acrobat Reader is software for browsing, on the computer display, a document described in PDF format, i.e. a document expressing format which may be printed to paper. This software enables browsing of a document, which is paginated like printed matter, through the step by step zooming, scrolling and page feeding. However, the feeling for browsing the these electronic documents is also far different from the feeling of browsing a book printed on paper, and such browsing cannot be said to be comfortable.
Browsing of an electronic document has mainly been conducted on the display of a desk-top type or notebook size personal computer. In the future, however, the necessity for browsing electronic documents in various conditions will be increased. For example, surely required in future is such an environment that an electronic document can be read comfortably even on the display of television receiver, for example, which may be installed in a living room or on the display of a hand-held information tool.
In the case of browsing an electronic document on the display screen of a television receiver as a home appliance, a user generally watches the television receiver in the living room maintaining a distance of several meters. Therefore, in comparison with the display of a personal computer, a virtual angle of the display screen observed by a user becomes narrow. Moreover, in the case of the hand-held information tool, there is a limitation in size of the display from the viewpoint of the hand-held property. In this case, even when display is given a higher resolution or when many characters are displayed on one display image, such a document cannot be read comfortably.
The existing browser is based on, like an ordinary computer display, use of the high resolution display screen from an area located within short distance. Namely, a document is displayed on the display screen in such a size as ordinary printed matter. Therefore, It is rather difficult to use to direct the television screen as the display screen when the television is watched in the distance of several meters and when the display area is narrow like the hand-held information tool.
However, when display of a document is magnified to enable easier browsing of characters, only a part of the document can be observed and the ease of browsing may be lowered.
In general, when a person reads a printed document, such as a newspaper, a person is often centralized to read the characters or observe the photographs of the interested portion. In this case, a person can change his consciousness continuously to the individual items from the entire part only by moving his eyes. Therefore, it is desirable to realize the same sense on the display screen.
Therefore, it may be thought that a document will be required to be displayed while it is continuously magnified or compressed. Namely, the entire part of paper is first displayed in such a size as enabling to read large headlines and photographs, and then the interested portion is continuously displayed through magnification up to the size enabling easier browsing thereof by manipulating a remote controller or the like. In this case, it is essential that display size may be changed continuously in order to attain the same sense as browsing the news paper as the printed matter.
Moreover, an electronic document displaying means such as an existing WWW browser or the like is based on manipulation using a mouse, but since the mouse is based on use on the desk, it is inconvenient to use the mouse at the area other than the desk top such as the living room or the like. When considering use under variable conditions, it is preferable to use a remote controller which may be manipulated only with a single hand. Among the personal computers which are already available in the market, a joy stick as an infrared remote controller or cursor moving button, etc. are used in place of the mouse to move the cursor on the display screen. In the browser having the user interface designed based on manipulation by the mouse, it is not comfortable to use such a remote controller for the manipulation. Therefore, a user interface applicable to manipulation by the remote controller is necessary.
In the browser based on the existing mouse, when the mouse cursor is assigned to the part where the link is defined among the document being displayed and it is then clicked, the linked document is then displayed in place of the current document. One of the general problems of this method is that since the part where the link is defined in the document is considerably small, it is not easy to realize manipulation on the display screen being isolated from a user, or to move and select the cursor by manipulation of a remote controller. In order to solve this problem, it is essentially required to provide a user interface which can easily realize going up to the link destination even with rough remote controller manipulation.
Another problem of the existing browser is that the currently displayed document disappears when the link is clicked, and thereby, a displayed page is jumped to the document page of the link destination and thereby spatial continuity is interrupted. With this discontinuity, a problem arises that a user cannot detect that a page of the linked document being read will be generated.
In order to solve the problems explained above, it is thought to propose a method to define a virtual space similar to the single and continuous three-dimensional space in which a person is living with familiarity in view of recognizing the current place of a person as the spatial position. In the electronic document browsing environment, a document is distributed to such single and continuous space to reach the desired document through the continuous spatial movement. For this purpose, it is required to move to the link destination without any jump.
In the browser of the related art, the desired position of the document is displayed by scrolling display contents of the window in regard to a long document which cannot be accommodated within the window. However, it is difficult during the scrolling to read the document because display contents moves at a high speed and it is not comfortable to read a longer document by scrolling. Moreover, since the position where a certain information is displayed among the display page is not constant when the scrolling is stopped, it is difficult to memorize the position of information among the position on the page.
In order to solve this problem, there is proposed a document browsing method in which a document similar to a book, as a printed matter, is displayed on the display of a personal computer, etc. and then browsing can be realized while changing over the pages. Currently however, the sense of changing over the pages is far different from that of a book, and it is also impossible to search the items by sequentially changing over the pages of a magazine. In order to realize more comfortable browsing, it is essential to realize the sense which is further similar to that of the printed matter.
The U.S. Pat. No. 5,341,466 by Kenneth Perlin and Jacob Schwartz discloses a user interface technology in which at least one two-dimensional reference plane is defined. Information accumulated within the computer is expressed by the representation object arranged by defining position and scale on the reference plane, and a part of the reference plane is displayed through magnification and compression thereof with two dimensional zooming.
In the above U.S. Pat. No. 5,341,466, since an individual information expression format is used, the information in which a mutual relationship can be defined by the hierarchical link, such as a directory of a computer and the WWW (which are the existing information expressing format) cannot be dealt without any modification. In the present invention, there is provided a means for browsing, by continuously following the link, the information in which a mutual relationship is defined by the hierarchical link to the other information from a certain information, namely the information of the so-called hypertext format, which is the general information expressing method from the related art.
In U.S. Pat. No. 5,341,466, all objects are arranged on a reference plane by defining the position and scale for the reference plane and a hierarchical relationship is not defined between these objects. However, the information such as an electronic document can be processed easily in many cases by defining the hierarchical relationship between objects. For example, when a highly ranked object is moved regarding a plurality of objects which are in the hierarchical relationship in the meaning, the lower ranked objects have to be moved depending on such highly ranked objects. Since the hierarchical relationship is not defined in U.S. Pat. No. 5,341,466, such a process is impossible.
In U.S. Pat. No. 5,341,466, the object itself and the reference plane in which the objects are arranged are limited to two-dimensions and an image displayed on the display screen displays in two dimensions in direct a part of the reference plane. However, for a greater understanding of information and for enabling expression of electronic information of variable mode, it is more preferable to execute a three-dimensional arrangement of the positional relationship of the information and to change in three dimensions the field of vision.
In U.S. Pat. No. 5,341,466, a means for displaying information which is not previously accumulated in the computer is not disclosed. However, on the occasion of browsing the WWW, information must be acquired from a network outside the computer, depending on necessity. In the case of a WWW browser of the related art, such as Microsoft Internet Explorer and Netscape Navigator, information at the link destination has been obtained when the mouse is clicked at the position where there is a link on the document. In the case of browsing the WWW using the zooming function, information as the display object must be obtained from the outside of computer depending on the zooming manipulation.
In U.S. Pat. No. 5,341,466, position and scale of each object for the reference plane must previously be defined. However, in the information of the format existing previously such as hypertext on the WWW and a directory of a computer, position and size for the reference plane are not previously defined in many cases and only the link to the other document from the document as the link source is defined. In the case of the WWW, the link to the other document from the particular area on the link source document is defined. In order to read such information through the zooming function, a means for determining the position and scale of the link destination document for the link source document is necessary.
It is therefore an object of the present invention to solve the problems explained above.
To solve the problems explained above, several pieces of electronic information are arranged, in the present invention, within a virtual space on the basis of link information defined in a document defining data such as electronic information, etc. The field of vision is defined to observe the inside of space, and an image of the virtual space including electronic information is generated based on such field of vision, and is then displayed on the display apparatus. Moreover, relative positional relationships between the electronic information and the field of vision in the virtual space is continuously changed on the basis of a user""s instruction. An image based on such field of vision is then continuously generated on the real time basis and it is then displayed on the display apparatus. Therefore, a user is capable of reaching the electronic information in which the link of the hypertext format or other link definition formats is extended and browsing through the magnified or reduced display while continuously moving the field of vision in the virtual space.
In order to realize the environment explained above, an electronic information browsing apparatus can be realized with the structure illustrated in FIG. 1. As set forth below, each drawing of the present specification corresponds to an embodiment for processing an electronic document described by a hypertext language such as HTML and therefore electronic information is described as an electronic document or only as a document.
This apparatus includes an electronic information definition data acquiring means, an electronic information definition data storing means, an electronic information definition data storing means, an electronic information definition data management means, an electronic information definition data analyzing means, a page image generating means, a page image storing means, a display image generating means, a display image storing means, an image output means, a user instruction accepting means, an electronic information layout information storing means, an electronic information layout information generating and updating means, a visual field information storing means and a visual field information updating means.
In above structure, the electronic information definition data acquiring means acquires the electronic information definition data from the network such as the Internet, broadcast, or another information transfer medium or information storing medium.
The electronic information definition data storing means stores the electronic information definition data acquired by the electronic information definition data acquiring means or the electronic information definition data generated on the present apparatus.
The electronic information definition data storing means temporarily stores the electronic information definition data for the purpose of making reference from the electronic information definition data analyzing means and page image generating means, etc.
The electronic information definition data management means performs management and distribution of electronic information definition data required by the other modules such as management of electronic information definition data to be stored in the electronic information definition data storing means and acquisition of electronic information definition data via the electronic information definition data acquiring means.
The electronic information definition data analyzing means analyzes the electronic information definition data and acquires the information to be used for generation of page image and generation of document layout information.
The user instruction accepting means is formed of an input device such as remote controller or the like, an interface means for such input device and a software or the like in order to accept a user""s instruction and transfer it to the other module. The electronic information layout information storing means stores the electronic information layout information for defining information regarding layout in the virtual space of the electronic information linked by the hypertext structure.
The electronic information layout information generating and updating means generates the electronic information layout information based on the analysis result of the electronic information definition data and also updates the electronic information layout information depending on change of visual field information.
The visual field information storing means stores the visual field information to define the area as the object for generation of a display image in the virtual space.
The visual field information updating means updates the visual field information based on the user""s instruction accepted by the user instruction accepting means.
The page image generating means generates image of each page of the electronic information using the electronic information definition data and its analysis result.
The page image storing means stores temporarily the page image generated by the page image generating means.
The display image generating means continuously generates the display image based on the electronic information layout information and visual field information.
The display image storing means temporarily stores the display image generated by the display image generating means. The image output means continuously outputs the display image stored in the display image storing means.
With the structure explained above, electronic information having the hypertext structure is arranged in the virtual space, the image which has observed the inside of the space based on the defined visual field is displayed on the display device and a user is capable of reaching the electronic information by following the link while continuously moving the visual field within the space and also browsing the electronic information while virtually changing the appearance.
Moreover, the electronic information browsing apparatus of the present invention may introduce the structure explained below.
In addition, the electronic information browsing apparatus of the present invention may introduce the following structure. Moreover, the virtual space explained above should be the three dimensional space and the visual field information updating means changes continuously in three dimensions the positional relationship between the visual field and electronic information based on user""s instruction and thereby the display image generating means generates the display image which changes continuously on the realtime basis. Therefore, the display image generating means is provided with a means for drawing the page on which a page image is adhered on the display image through the high speed perspective transformation.
With this structure, an image of smooth moving in such a case that the visual field is continuously moved in the virtual three dimensional space may be displayed.
The electronic information layout information generating and updating means determines, on the basis of the analysis result of electronic information definition data by the electronic information definition data analyzing means, the relative position of the electronic information at the link destination for electronic information or the page at the link source in the virtual space and also generates, based on this position, the electronic information layout information and the electronic information layout information memory means stores its electronic information layout information.
With this structure, the relative positional relationship between linked pieces of electronic information in the virtual space can be determined automatically from the electronic information definition data.
The electronic information layout information generated by the electronic information layout information generating and updating means may be determined to define the electronic information layout in which the electronic information of link destination, for example, is arranged in small size at the area before the electronic information of the link source. FIG. 4 illustrates an example of generation of the display image based on such electronic information layout information.
With this structure, the electronic information of link destination is arranged through compression before the electronic information of the link source and is then displayed on the display area.
As the other realizing method of the electronic information layout information generated by the electronic information layout information generating and updating means, it is also possible to layout the electronic information in the link destination in small size behind the electronic information of the link source. In this case, the display image generating means displays through semi-transparency the electronic information of the link source depending on change of visual field and thereby the electronic information of the link destination may be observed through such information of link source.
With the structure explained above, the electronic information of the link source may be arranged through compression in the deeper side of the electronic information of the link source and thereby the deeper electronic information can be displayed on the display area through the before hand electronic information.
Regarding the electronic information defined to be composed of a plurality of pages in the electronic information defining data and the electronic information which cannot be displayed within a page, display is performed in the similar manner to that of a book including a plurality of pages and the electronic information layout information generating and updating means may be formed, in order to realize the display explained above, to generate the electronic information layout information including the information to define the page layout in the electronic information in the virtual space explained above. In this case, an example of a display image is illustrated in FIG. 5.
With the structure explained above, display similar to that of the book including a plurality of pages is performed for the electronic information not accommodated in one page.
In the electronic information layout information explained above, the absolute coordinate of each electronic information in the virtual space is never defined but it is possible to introduce the structure to define the relative positional relationship of the electronic information of the link destination for the electronic information of link source or the page for all links between electronic information. Thereby, relative positional relationship of all linked electronic information and pages can be established. Moreover, only one electronic information among these information is selected as the representative electronic information and the relative positional relationship between the visual field and representative electronic information can be defined as the visual field. Thereby, the relative positional relationship between the all electronic information linked and visual field can be established. FIG. 7 illustrates an example of such data format and FIGS. 8A, 8B, and 8C illustrate an example of items of data described in FIG. 7.
With this structure, a geographical relationship among electronic information can be defined for each link between the electronic information and moreover only one of the electronic information is selected as the representative electronic information and the geographical relationship of all electronic information combined by the link can be defined with reference to the representative electronic information.
FIGS. 9A and 9B are diagrams for explaining a definition of a positional relationship between the visual field and electronic information in the virtual three-dimensional space as explained above.
First, viewpoint coordinate system is defined in the three-dimensional space and viewpoint is defined to exist at the position of origin. The visual field, namely area displayed on the display area is projected, in regard to the viewpoint explained above, to the virtual display area fixed on the viewpoint coordinate system. When the virtual display area is formed as the rectangular shape, the visual field is defined as the area of pyramid.
In FIGS. 9A and 9B, the X, Y, Z axes of the viewpoint coordinate system are indicated by vectors vx, vy, vz. The virtual display area is formed as the rectangular shape placed in parallel to the XY plane and its center is located on the Z axis. Therefore, in this case, the point corresponding to the center of display area, namely the gaze point is located on the Z axis of the viewpoint coordinate system in the virtual space.
In the same space, the reference plane and reference plane coordinate system are defined. Here, the reference plane is assumed to be fixed in the reference plane coordinate system. For example, the XY plane of the reference plane coordinate system is assumed to be matched with the reference plane. Moreover, the electronic information coordinate system is defined for each electronic information arranged in the three-dimensional space. In addition, the page coordinate system is also defined for each page included in each electronic information.
Change of visual field for the electronic information is realized by changing the geographical relationship of the reference plane coordinate system for the viewpoint coordinate system, while the geographical relationship between the reference plane coordinate system and electronic information coordinate system of each electronic information are fixed.
Here, it is assumed in the initial condition that the representative electronic information is determined and position of representative electronic information in the viewpoint coordinate system is also established. The reference plane coordinate system is determined with reference to the position of representative electronic information. Determination is made so that the page plane, for example, of the representative electronic information is almost matched with the reference plane and the representative electronic information as a whole is accommodated in the range of the standard coordinate value in the reference plane coordinate system, for example, in the range of xe2x88x921.0 to 1.0.
In actual, in the case where the reference plane coordinate system is set in such a manner as being matched with the information coordinate system of electronic information selected as the representative electronic information on the occasion of previously defining each electronic information coordinate system, when each electronic information coordinate system is defined to satisfy the reference explained above, the electronic information coordinate system of the representative electronic information can be defined in direct as the reference plane coordinate system and therefore procedures for determining the reference plane coordinate system can be saved.
The geographical relationship between the reference plane coordinate system and representative electronic information coordinate system is determined when a new representative electronic information is determined and it is never changed while such electronic information is the representative electronic information.
With introduction of such structure, the reference place coordinate system which has established the geographical relationship is defined for the coordinate system of the representative electronic information and change of visual field can be realized by changing the geographical relationship of visual field for the reference plane coordinate system. Moreover, when the representative electronic information is changed, the reference plane coordinate system can be determined automatically based on the position of a new representative electronic information.
In the system explained above, in order to assure excellent accuracy and efficiency of the display process, a means for determining the representative electronic information most suitable to assure the representative electronic information among the linked electronic information and a means for changing the representative electronic information depending on such determination are provided to change the representative electronic information to always select the optimum representative electronic information. The representative electronic information as the optimum representative electronic information should enable easily reaching all electronic information to be displayed within the display area and should have the standard value as the scale for the visual field.
With this structure, the representative electronic information may be changed automatically to maintain excellent accuracy and efficiency for the display process.
In a method for determining the representative electronic information, the condition for shifting a candidate of representative electronic information to the electronic information in the link source or link destination from the current representative electronic information candidate, when the current representative electronic information is defined as the representative electronic information candidate and the condition to shift such representative electronic information candidate to the electronic information in the link source or link destination is established, the representative electronic information candidate is shifted depending on the conditions, the same process is repeated for a new representative electronic information and when the representative information candidate is no longer shifted, such representative electronic information candidate is established as the representative electronic information.
According to this structure, the representative electronic information is automatically determined on the basis of the representative electronic information selecting condition.
In order to maintain continuity in the shifting of visual field, it is necessary to suppress generation of non-continuous change of display area even when the representative electronic information is changed. On the other hand, in order to keep accuracy of arithmetic process, geographical relationship between the viewpoint coordinate system and reference plane coordinate system, coordinate system of the representative electronic information must be accommodated within the constant range. For this purpose, when the representative electronic information is changed, the geographical relationship of the reference plane coordinate system for the viewpoint coordinate system is normalized without virtual change of display area. In more practical, after the representative electronic information is changed and relationship between the representative electronic information coordinate system and reference plane coordinate system is established, the geographical relationship of the reference plane coordinate system for the viewpoint coordinate system is magnified or compressed centering around the viewpoint so that the distance up to the noted gaze point on the reference plane from the viewpoint in the viewpoint coordinate system becomes equal to the predetermined reference distance (for example, 1.0). As a result, all objects in the space are likely magnified or compressed centering around the viewpoint while virtual change of display on the display area is never conducted. After the representative electronic information is changed and normalized as explained above, continuous change of the visual field of the display area can be realized by continuously changing the visual field information to define the geographical relationship between the visual field and reference plane.
With introduction of the structure explained above, the information for defining geographical relationship between the reference plane coordinate system and visual field can be normalized while virtual change of display area is never conducted.
Here, the visual field information includes, as the parameters, the noted viewpoint position on the reference plane, rotating angle of the reference plane passing the gaze point on the reference plane and considering the straight line vertical to the reference plane as the axis, tilt angle for defining rotation of the reference plane passing the noted gaze point on the reference plane and considering the straight line parallel to the horizontal direction of virtual display area as the axis, scale ratio of the reference plane coordinate system for the viewpoint coordinate system and visual field angle.
A set of above parameters is effective to fix the distance up to the noted gaze point on the reference plane from the viewpoint in the viewpoint coordinate system, but the similar effect can be obtained on the display area even by fixing the scale ratio and then changing, as the parameter, the distance, in place of it, up to the noted gaze point on the reference plane from the viewpoint.
When the visual field information is defined as explained above, relationship between the reference plane coordinate system and viewpoint coordinate system is defined by parameters and the visual field can be changed by changing this parameter.
Here, it is also possible to provide the structure that change during the unit time is proportional to the distance, in order to make constant a degree of change of visual field which a user feels, up to the noted gaze point on the reference plane from the viewpoint with reference to the viewpoint coordinate system, regarding the noted viewpoint position on the reference plane among the parameters explained above.
The viewpoint information updating means continuously updates parameters of visual field information explained above on the basis of user instruction accepted by the user instruction accepting means, while the display area generating means generates continuously the display area using visual field information, electronic information layout information and page image. A user issues an instruction for shifting the visual field with a remote controller while verifying the display area and reads the electronic information by shifting the visual field.
According to this structure, virtual shifting speed of electronic information on the display area can be kept almost constant.
In order to display an electronic information including a plurality of pages like a book, the electronic information layout information is provided with a page coordinate system for each page of the electronic information in view of defining the geographical relationship of the page coordinate system for the electronic information coordinate system. The user instruction accepting means accepts the instruction for turning the pages from a user and the electronic information layout information generating and updating means changes, when a user has issued the instruction to turn the page, the geographical relationship of the page coordinate system for the electronic information coordinate system.
In the electronic information including a plurality of pages like a book, the geographical relationship of the electronic information coordinate system of the information of link destination for the page coordinate system of the link source page should be defined in the electronic information layout information in order to arrange the compressed link destination electronic information on the link information of each page.
With the structure explained above, display for turning the page on the display area may be realized for the electronic information including a plurality of pages.
The electronic information definition data having the hypertext structure existing on the network or the like is thought to be linked endlessly and therefore it is required to acquire only the necessary electronic information definition data from such data for preparation of display and actual display operation.
For this subject, the electronic information layout information generating and updating means and display image generating means are provided with the link search condition and link search condition determining means. The link search condition determines the condition for continuation of link search on the occasion of following the link in the link source direction or in the link destination direction. Moreover, as the data items of electronic information layout information, the electronic information display priority and page display priority are also provided.
The electronic information layout information generating and updating means follows the electronic information layout information depending on the link search condition to obtain the electronic information definition data required for generation and update of the electronic information layout information and the result of analysis of such data in order to generate and update the electronic information layout information. In this case, the electronic information layout information generating and updating means calculates display priority of the electronic information and page on the basis of the geographical relationship for the visual field and then updates the electronic information layout information.
The page image generating means refers to the electronic information layout information and when the display priority of electronic information and page becomes highest, it generates the page image on the basis of the electronic information definition data and result of its analysis and the page image storing means stores the generated page image. The electronic information definition data explained above reads the data stored in the electronic information definition data storing means or acquires the data via the electronic information definition data acquiring means. In the case where the electronic information definition data is used from the electronic information definition data analyzing means or page image generating means, the electronic information definition data storing means may be used as illustrated in FIG. 1.
The display image generating means sequentially follows the link of the electronic information layout information based on the link search condition and determines whether each electronic information or page should be displayed or not based on the electronic information display priority and page display priority and also generates the display image depending on such display priority. In more practical, threshold value of display priority is provided and drawing is performed on the display image only for the electronic information and page having the display priority higher than the threshold value.
According to this structure, only the data related to display is acquired from the electronic information definition data linked by the hypertext structure on the network considered to have endless link structure and preparation for display and actual display are conducted.
Regarding the electronic information or page to be displayed in the display image generating means, half-transparent display is conducted for the electronic information having the display priority lower than the predetermined reference value and the half-transparent display is conducted by increasing the transmissivity for the information having lower display priority.
According to this structure, with change of display priority of electronic information due to the shifting of the visual field, display condition is changed from the transparent and invisible condition because the display priority is lower up to the non-transparent and perfect visible condition because display priority is higher.
In view of realizing effective display image generation even if virtual size of the electronic information or page on the display image is changed due to the change of visual field information, the page image generating means is provided with a means for generating page images in a plurality of different resolution for one page. Thereby, when the page image is generated, the page images of a plurality of different resolution are generated and are then stored in the page image storing means. While, the display image generating means selects the page image of the resolution enabling generation of a display image in the highest efficiency for the use in the generation of the display image.
According to this structure, the page image in the resolution enabling the most efficient image generation in the display image generation is selected for use in the image generation.
The electronic information definition data as the display object is not limited to stationary data and may be the data, for example, to define the dynamic content like a program. In this case, the page image generating means updates temporarily the page data depending on definition of the electronic information definition data.
Moreover, it is also possible that the electronic information definition data itself is not acquired from the outside and it is generated dynamically with a program included within the browsing apparatus.
According to this structure, the electronic information having dynamic content may be displayed.
In addition, the electronic information definition data generating and editing means is provided so that a user can generate book mark data and electronic information definition data by re-arrangement of link to the existing electronic information. The electronic information definition data generated by user is stored in the electronic information definition data storing means for management with the electronic information definition data management means.
With this structure, a user can generate and store a bookmark and other electronic information definition data.
In order to realize the display of smooth movement during the shift of viewpoint or operation for turning the page in the display image generation by the display image generating means, generation of a display image of 30 frames per second or more is required. In order to satisfy this condition, electronic information and page having higher display priority is displayed precedingly and only the content of the range enabling generation of a display image in the display frame rate required depending on the condition is displayed. In one practical method, the frame image generating target time is set first, a forecasted value of drawing time required for drawing of electronic information is obtained for each electronic information stored in the electronic information layout information storing means, such forecasted values are accumulated in the sequence of higher display priority, threshold value of display priority is determined so that the accumulated value becomes less than the frame image generation target time and only the electronic information and page having the display priority higher than the threshold value are drawn.
In the other method, image generating time of immediately preceding frame is measured, a ratio of frame image generating time measured value for the frame image generating target time is obtained and the threshold value for suspending drawing due to the display priority is increased or decreased so that the next frame image generating time can be accommodated within the target time. In more practical, when the measured value is larger than the target time, threshold value is increased, but when the measured value is smaller than the threshold value, the threshold value is decreased.
The frame image generating target time is preferably changed depending on the condition. In more practical, during sifting of the visual field and operation for turning the pages, the frame image generation target time is set short to enable smooth generation of a moving image and when visual field is not shifted or operation for turning the pages is not conducted, the target time is set longer.
With the structure explained above, when display content changes quickly, display considering first the smooth movement is performed and when display content is rather lower, the frame display image generation time is set longer to realize the display of higher fidelity.
When a display image is generated in the display image generating means, if page image of electronic information to be drawn on the display image is not yet prepared on the page image storing means, the display image generating means does not adhere the page image for the relevant page and performs the simplified display such as the display of only the page mode.
The electronic information has been explained as the display object but three-dimensional cubic material and desired object may be selected as the display object in place of the electronic information.
According to this structure, even if preparation for page image is still insufficient, display considering first the smooth movement may be realized without waiting for such preparation.
The electronic information browsing apparatus explained above may be realized with a software by utilizing a desired computer. In this case, the software for realizing above functions with hardware of the computer is described and it is then recorded to a computer readable medium.
With such structure explained above, object having variable modes can be displayed in addition to two-dimensional electronic information.
The present as explained above may be formed to realize the functions of the present invention by browsing the software with a computer in order to realize the functions of the present invention stored in the memory medium.
Objects of the invention are achieved by an electronic information display method, which displays first electronic information on a display area; magnifies a part of the displayed first electronic information with a magnification factor; and displays second electronic information overlapping the first electronic information on the display area when the magnification factor exceeds a predetermined threshold factor.
Further objects of the invention are achieved by an electronic information browsing apparatus for browsing electronic information having embedded link information which describes a relationship with other electronic information, including a document layout and updating unit to determine a relationship of geographical layout to virtual space of an electronic information based on link information defined in an electronic information definition data; a visual field updating unit to define a visual field for observing the inside of the virtual space and to generate an image in virtual space including electronic information having a determined geographical layout based on the visual field definition and then to output the image to a display device; and a display image generating unit to continuously change the geographical positional relationship between the electronic information and the visual field in the virtual space according to an instruction input of a user and to continuously generate then output the image based on the visual field to the display device on a realtime basis.
Even further objects of the present invention are achieved by a computer readable memory medium on which a program for visually displaying electronic information is recorded, including code to display first electronic information on a display area; code to magnify a part of the displayed first electronic information with a magnification factor; and code to display second electronic information overlapping the first electronic information on the display area when the magnification factor exceeds a predetermined threshold factor.
Moreover, objects of the invention are achieved by a computer readable memory medium on which a program is recorded for browsing the electronic information in which the link information to describe the relationship with the other electronic information is embedded, including code for determining geographical layout to the virtual space of the electronic information based on the link information defined in the electronic information definition data; code for defining visual field to observe the virtual space to generate, based on the visual field definition, the virtual space image including electronic information having determined geographical layout and then output the image to the display device; and code for continuously changing the geographical positional relationship between the electronic information and visual field in the virtual space based on the user instruction input and then continuously generating, on the realtime basis, the image based on the visual field and outputting the image to the display device.